Can you provide some more information?
Are you using a normally-closed mechanical switch, or an inductive proximity sensor, or an optical or hall-effect switch, or something else?
Are you trying to use port 1 pins 3 and 4 as inputs? You should be able to use only a single input for a home or limit switch. Do the BOB terminal numbers correspond to the LPT port pin numbers? If not, what is the mapping between BOB terminal numbers and LPT port pin numbers?
If you are using a mechanical switch, do you have a pull-up resistor wired to the NC switch contact and +5 volts?